Is it still acceptable to put limits on strangers kids?

When I was a kid, I have vivid memories of strangers telling me not to do x, y or z, yelling at me if I did something wrong, and confronting my mother about it if I was being too obnoxious. I feel like the situation has completely flipped nowadays, and at worst you will get into a fight with the parents if you try to confront them.

I was on a train yesterday, and the people sitting next to me had a toddler. This toddler had no limits at all, cried all the way from Biel to Lausanne, spat on me multiple times, kept grabbing my legs with dirty hands, drooled all over the seats and threw a tantrum when I refused to give a piece of my food. The parents did not give a flying damn about their children, and also looked really angry because I did not give him a piece of my cookie.

I really wanted to confront the parents, but as they were not from here, I was scared they would take it extremely negatively and argue with me.

How are we supposed to act in situations like this? Would you have confronted the kid/parents directly?